Muscle is becoming one of the prime target tissues for gene therapy of not only intrinsic muscle disorders (i.e.,muscular dystrophies) but for common and prevalent disorders. It can be used as a site for genetic vaccination and as a platform for the secretion of cytokines, hormones, and growth factors. We have developed a new cationic polymer system that condensed pDNA into a small particle and that is effective at transfecting muscle tissue. The Phase I application proposes to optimize several factors of the novel cationic polymers for intramuscular delivery of DNA. During the Phase II studies, the polymer optimization will be completed, and an investigation begun into the mechanism of action for this class of polymers. From this data, an optimized polymer will be developed and tested for efficacy and toxicity. Phase III will lead to the development of a formulation that can be commercialized by internal development and licensing to other companies. PROPOSED COMMERCIAL APPLICATIONS: Cationic polymers developed under this proposal should enable efficient delivery of DNA to muscle tissue. This delivery method will effect genetic vaccines, the treatment of intrinsic muscle disorders, and can be used as a platform for the secretion of cytokines, hormones, and growth factors (through muscle). They will be commercialized by internal development and licensing to other companies.